Abstract

Purpose

Cement augmentation of pedicle screws is able to improve screw anchorage in osteoporotic vertebrae but is associated with a high complication rate. The goal of this study was to evaluate the impact of different cement volumes on pedicle screw fatigue strength.

Methods

Twenty-five human vertebral bodies (T12–L4) were collected from donors between 73 and 97 years of age. Bone density (BMD) was determined by quantitative computed tomography. Vertebral bodies were instrumented by conventional pedicle screws, and unilateral cement augmentation was performed. Thirteen vertebrae were augmented with a volume of 1 ml and twelve with a volume of 3 ml bone cement. A fatigue test was performed using a cranial–caudal sinusoidal, cyclic load (0.5 Hz) with increasing compression force (100 N + 0.1 N/cycles).

Results

The load to failure was 183.8 N for the non-augmented screws and was increased significantly to 268.1 N (p < 0.001) by cement augmentation. Augmentation with 1 ml bone cement increased the fatigue load by 41% while augmentation with 3 ml increased the failure load by 51% compared to the non-augmented screws, but there was no significant difference in fatigue loads between the specimens with screws augmented with 1 ml and screws augmented with 3 ml of bone cement (p = 0.504).

Conclusion

Cement augmentation significantly increases pedicle screw stability. The benefit of augmentation on screw anchorage was not significantly affected by reducing the applied volume of cement from 3 ml to 1 ml. Considering the high risk of cement leakage during augmentation, we recommend the usage of a reduced volume of 1 ml bone cement for each pedicle screw.

Graphic Abstract

These slides can be retrieved under Electronic Supplementary Material .

中文翻译：

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减少的水泥体积不会影响椎弓根螺钉的螺钉稳定性。

摘要

目的

椎弓根螺钉的水泥增强能够改善骨质疏松椎骨的螺钉锚固，但并发症发生率较高。这项研究的目的是评估不同水泥用量对椎弓根螺钉疲劳强度的影响。

方法

从73至97岁的供体中收集了25个人体椎体（T12–L4）。骨密度（BMD）通过定量计算机断层扫描确定。用传统的椎弓根螺钉器械固定椎体，并进行单侧骨水泥增强。用1毫升的体积增加13块椎骨，用3毫升的骨水泥增加12块椎骨。疲劳测试使用的是颅－尾正弦循环载荷（0.5 Hz），压缩力不断增加（100 N + 0.1 N /循环）。

结果

非增强螺钉的破坏载荷为183.8 N， 通过水泥增强显着增加至268.1 N（p <0.001）。与未加筋的螺钉相比，加1 ml骨水泥增强的疲劳载荷增加了41％，而加筋3 ml的增强增加了51％的破坏载荷，但是加1的螺钉在试样之间的疲劳载荷没有显着差异毫升和螺钉加3毫升的骨水泥（p  = 0.504）。

结论

水泥增强显着提高椎弓根螺钉的稳定性。通过将水泥的涂抹量从3 ml减少到1 ml，不会明显增加螺钉固定的好处。考虑到增强过程中水泥渗漏的高风险，我们建议每个椎弓根螺钉使用减少量的1 ml骨水泥。

图形摘要

这些幻灯片可以在“电子补充材料”下找到。